We propose to use various electrochemical techniques and the electrocatalytic method to investigate properties of carbon-halogen cleavage reactions of PCB's and PBB's. Model biphenyls with one and two halogens, as well as their more toxic congeners, will be chosen for study. This work will yield new electrocatalysts for the destruction of PCB's and PBB's in organic and aqueous micellar media, E degree-values for the carbon-halogen reductions, and lifetimes of reactive intermediates. Results will provide a better understanding of environmental transformations of PCB's and PBB's, which often lead to more toxic products. E degree-values obtained will be useful in correlating reactivities of the title compounds in solar degradations and other environmental reductions. The research is expected to yield significant contributions to an eventual solution of the public health problem of PCB and PBB contamination. It should generate some new approachs to our long-term goal of developing methods for in-vivo monitoring of PCB's and PBB's and to degradative cleanup of contaminated materials. Furthermore, our results may aid in research aimed at elucidation of the mechanism of toxicity of these persistant pollutants.